Configure TDD in ionic2

Question

I followed the Joshua Moroney tutorial on Ionic2 and TDD, but got stuck trying to debug errors as they occurred.

Basic example:

import { TestBed, ComponentFixture, async } from '@angular/core/testing';
import { By } from '@angular/platform-browser';
import { DebugElement } from '@angular/core';
import { IonicModule, NavController } from 'ionic-angular';
import { MyApp } from '../../app/app.component';
import { TabsPage } from './tabs';

let comp: TabsPage;
let fixture: ComponentFixture<TabsPage>;
let de: DebugElement;
let el: HTMLElement;

describe('Page: Tabs Page', () => {

beforeEach(async(() => {

    TestBed.configureTestingModule({

        declarations: [MyApp, TabsPage],

        providers: [
            NavController
        ],

        imports: [
            IonicModule.forRoot(MyApp)
        ]

    }).compileComponents();

}));

beforeEach(() => {
    fixture = TestBed.createComponent(TabsPage);
    comp    = fixture.componentInstance;

});

afterEach(() => {
    fixture.destroy();
    comp = null;
    de = null;
    el = null;
});

it('is created', () => {
    expect(fixture).toBeTruthy();
    expect(comp).toBeTruthy();

});

});

The result of karma:

FAILED TESTS:
Page: Tabs Page
✖ is created
  PhantomJS 2.1.1 (Mac OS X 0.0.0)
  Chrome 57.0.2987 (Mac OS X 10.12.3)
TypeError: this.parent.unregisterChildNav is not a function
    at Tabs.ngOnDestroy (webpack:///~/ionic-angular/components/tabs/tabs.js:220:0 <- src/test.ts:56626:21)
    at callProviderLifecycles (webpack:///~/@angular/core/@angular/core.es5.js:11109:0 <- src/test.ts:11389:18)
    at callElementProvidersLifecycles (webpack:///~/@angular/core/@angular/core.es5.js:11078:0 <- src/test.ts:11358:13)
    at callLifecycleHooksChildrenFirst (webpack:///~/@angular/core/@angular/core.es5.js:11062:0 <- src/test.ts:11342:17)
    at destroyView (webpack:///~/@angular/core/@angular/core.es5.js:12280:0 <- src/test.ts:12560:5)
    at callViewAction (webpack:///~/@angular/core/@angular/core.es5.js:12391:0 <- src/test.ts:12671:13)
    at execComponentViewsAction (webpack:///~/@angular/core/@angular/core.es5.js:12333:0 <- src/test.ts:12613:13)
    at destroyView (webpack:///~/@angular/core/@angular/core.es5.js:12279:0 <- src/test.ts:12559:5)
    at callWithDebugContext (webpack:///~/@angular/core/@angular/core.es5.js:13060:25 <- src/test.ts:13340:42)
    at Object.debugDestroyView [as destroyView] (webpack:///~/@angular/core/@angular/core.es5.js:12614:0 <- src/test.ts:12894:12)
    at ViewRef_.destroy (webpack:///~/@angular/core/@angular/core.es5.js:10199:0 <- src/test.ts:10479:18)
    at ComponentRef_.destroy (webpack:///~/@angular/core/@angular/core.es5.js:9944:51 <- src/test.ts:10224:67)
    at ComponentFixture.destroy (webpack:///~/@angular/core/@angular/core/testing.es5.js:248:0 <- src/test.ts:40179:31)
    at Object.<anonymous> (webpack:///src/pages/tabs/tabs.spec.ts:40:16 <- src/test.ts:110812:17)
    at ZoneDelegate.invoke (webpack:///~/zone.js/dist/zone.js:365:0 <- src/test.ts:123570:26)`

This is testing a single component without complexity:

import { Component } from '@angular/core';

@Component({
  templateUrl: 'tabs.html'
})

export class TabsPage {

  constructor() {

  }
}

Can someone point me to a tutorial on how to solve these problems; not just provide a solution for this one problem?

Thank,

Andy

Answer 1

. : " NavController". NavController, mock . , ChildNav. . : https://github.com/ionic-team/ionic/blob/master/src/navigation/nav-controller.ts , , , :

public registerChildNav(nav: any) {
  // do nothing
}

public unregisterChildNav(nav: any) {
  // do nothing
}

( mocks test-mocks , src):

import { NavController } from 'ionic-angular';
import { NavMock } from '../../../test-mocks/mocks';


providers: [
  //NavController,
  {
    provide: NavController,
    useClass: NavMock
  },
]

.